By ITV News Multimedia Producer Suzanne Elliott
On Monday, Prime Minister Boris Johnson once again put England into lockdown until at least February 15 following a huge spike in coronavirus cases.
The rapid rise in infections is being fuelled by a new mutation of Covid-19 that is likely to have originated in South East England.
The new variant of Covid is up to 70% more transmissible and is spreading in a "frustrating and alarming" manner, Mr Johnson said in his televised address to the nation.
Another mutation from South Africa was also identified at the end of 2020.
Amid the gloom of Mr Johnson's address, was a slither of hope in the form of the vaccine, but the prime minister caveated the speed at which the UK will be in a position to ease restrictions with several 'ifs', one being that “our understanding of the virus doesn’t change dramatically once again".
But could it? Could more highly transmissible variants be around the corner? And how is science keeping - if not ahead - up with the virus?
Is it normal for viruses to mutate?
Yes. All viruses mutate - some quicker and more efficiently than others.
“SARS-CoV-2, the virus which causes Covid-19 is evolving and mutating all the time, as do all similar viruses," Prof Tom Solomon, the Director of the NIHR Health Protection Research Unit in Emerging and Zoonotic Infections, at the University of Liverpool says.
Many of these mutations will not be significant or cause for concern, says Dr Jeremy Farrar, Director of Wellcome.
“But some may give the virus an evolutionary advantage which may lead to higher transmission or mean it is more harmful."
What is a mutation?
In very simplistic terms, a virus drops off a set of instructions into a cell in the body and those instructions are followed by the cell to make more new viruses.
The instructions are then replicated and each new virus that is made receives a single copy of those replicated instructions.
But sometimes there is a mistake in these instructions.
Dr David Matthews, Reader in Virology at University of Bristol explains it is like you writing out a string of 30,000 letters by hand over and over again - the chances are you will make a typo at some point.
When one of these new viruses carrying a typo infects a new cell, the cell may look at the instructions and - unable to understand them – the process of making new viruses will fail.
But other times the instructions will still make sense and new viruses will be made that merrily replicate the mutated code and may even add more typos.
That may not always mean much. This change does not always make a difference; it may not necessarily help or hinder the virus.
But in another scenario, the newly tweaked instructions may give an advantage to the virus - perhaps the slight mutation can now replicate faster, or the spike protein is now better able to attach to the next cell.
"Instead of getting 100 new viruses from every cell, maybe you get 120 new viruses from every cell and then that person becomes full of the new virus" explains Dr Matthews.
This new virus then spreads to another person - a mutation only makes its mark when it starts replicating in other people.
Dr Matthews sums it up: "You've got a virus in a cell; the virus makes a mistake, that mistake means that the individual virus now replicates slightly faster in that individual. Then this new virus infects another individual and it continues to dominate and so on and so forth. And now what you've got now is a variant."
Why does a virus mutate?
But far from being an "evil, malevolent creature" doing all it can to survive, mutations are a simple mistake that give the virus a fighting chance.
The virus is simply, as Dr Matthews says, “doing what it can to get by”.
Dr Matthews says that "at some stage that virus is going to find a version of itself, that was slightly better and spreading between individuals in each new host."
"We're not fighting against a hive mind," says Dr Matthews. "It's pure, dumb, blind evolution".
Are there other variants?
While the South East variant and the South African variant have made the headlines, there have been many genetic variants of Covid-19 identified since the disease was first understood.
For the first 12 months of the outbreak, one dominated, but the virus is under renewed pressure to evolve as so many millions of people have now become infected.
There is now known to be a Nigerian variant and there are likely to be many more.
Dr Matthews points out that the new variant was found in the UK because British scientists lead the way in genomics, while other mutants elsewhere may have been missed.
Is Covid-19 behaving differently to other viruses?
Dr Julian Tang, Honorary Associate Professor/Clinical Virologist Respiratory Sciences at the University of Leicester says that while “the UK variant is very unusual” at this stage in the human-virus relationship it is something virologists expect to see.
"If you compare all the viruses in the world that have been sequenced so far - some several hundred thousand of them - the differences between the viruses are actually very small - between two different viruses there might be eight to 10 different mutations between them so it's not very rapidly mutating at all.
"However, when you put the new virus into a new host the mutation rate tends to be accelerated because the new virus is trying to adapt to the new host. And during that process the host may get a more severe disease.
"But over time the virus and the host will adapt to each other, and you get to the kind of symbiosis where we can transmit quickly, and rapidly like seasonal flu, without killing the patient most of the time."
And not only is that best for humans, but also best for the virus which will die out if it keeps killing its host.
While virologists agree there are few surprises with Covid-19, Dr Tang does say the long term complications of Covid are something we do not usually see with viruses.
How do we know about these mutations?
The lexicology and process of infectious diseases might be new to many of us in 2020, but to virologists this is a very familiar place.
"This pandemic has really revealed the daily workings of a virus laboratory to some extent. We look at, we do resistance testing," Dr Tang says.
Coronaviruses are RNA viruses and the newly-discovered virus SARS-CoV-2 has a single short RNA strand that is just 30,000 letters long. These letters can be ‘read’ one by one, using a technique called sequencing that can identify mutations.
Even in normal times, scientists are tracking and sequencing viruses in labs around the world and it is all "quite routine".
There is a network of collaborating laboratories around the world - Melbourne, Australia, Tokyo, London - that are collecting and examining flu virus samples, “looking for surprises” - it is just that most of the time, the world pays no attention.
"What they are looking for is either drug resistance mutations or any other mutation that might actually compensate for these mutations and lead to higher transmissibility to some extent," Dr Tang says.
"They then sequence the virus and compare it to a reference virus sequence, and look at the clinical details.
"Sometimes they grow the virus and culture in the presence of different drugs and measure the viral load, and replication rate in culture.
"And then those which look suspicious, they might even move to animal models to look for enhanced transmissibility and or resistance in that way."
Should we be confident that it will still respond to the vaccines?
The scientific community is cautiously optimistic, but warns there are still so many unknowns.
Dr Matthews says: "The further and faster we roll out the vaccine programme, the more we'll be putting the virus under evolutionary pressure, because, now suddenly lots of people will have an immune response that is effective.
"Any virus that can cope with that by acquiring mutations will mean your immune response isn't as effective, and that virus will probably start to dominate.
"Once we've rolled the vaccine out, over time, the virus could adapt again.
"And then the question will be, if it adapts again, will it adapt to the point where we need to change our vaccine again?"
Dr Matthews points out that is an impossible question to answer right now, but vaccine escape mutants are seen with many viruses, warns Dr Tang, including flu and hepatitis B and says it is likely that the Oxford/AstraZeneca vaccine in particular will have to be changed in a few years.
But "rejigging the vaccine will be very rapid", says Dr Matthews.
He also says the other vaccines in production - of which there are around 200 - "could offer the kind of protection that the virus simply can't evade," or forces the virus to change in a way that means that it is no longer particularly dangerous.
That mutations that allow the virus to sidestep the vaccine may be less severe is another slither of good news.
“When it eventually infects most of the world's population, that mutation rate will increase, because you have a much higher population of replicating viruses, that mutation can arise from.
"But the direction of mutations should be towards a more benign - possibly more transmissible for the virus - because that's what adaptation does.
“It would be passed on more easily, but it wouldn't be as deadly.”